The best you could do would be to run Steam under the qemu processor emulator. However, you would be very lucky to get even as much as one frame per second on any 3D game. Maybe a simple game, like a card game, that doesn't use 3D acceleration might be barely playable. Basically, emulating the x86 on a Raspberry Pi, I would guess would give you about the performance equivalent of a 80486. Just using qemu to run Steam just to chat with online Steam buddies may work fine, but would be about as unsupported as you could get.

Now...if you instead talk about *some* mini-ITX boards with a AMD APU , cut down resolution all the way to 800x600 and cut graphics effects all the way down also and you might get a minimal decent FPS to play (anything in the 30-40 FPS range or slightly better is perfectly acceptable) .

You slap some RAM and a simple fan (it might even work out w/o the fan but you can get a real silent and inexpensive one ) in one of those mini-ITX and get a minimal Linux machine for gaming...

...all that still with a very small price tag and lower power drain ....

If the Android 4.0 port for Raspberry Pi is finished (see http://www.raspberrypi.org/archives/1700) I guess that the Steam Mobile app could be adapted to work on a Raspberry Pi (http://store.steampowered.com/mobile/) giving you access to chat, store and so on. I still think that even this is unlikely. Because of the reasons mentioned in this thread, I don't see the "real" Steam on Raspberry Pi happening at all.

Steam needs 1 GHz minimum to run. The Rasberry Pi does 1 GHz on max overclock, which would destroy it. Then there's the ARM/x86/x64 problem. The games would need to be recoded to run. It would not be viable. I was surprised by how damn powerful its GPU is for something so cheap. I suppose you COULD get Half-Life 1 running, but because of wine, and the new remake, Black Mesa, I doubt it.

This question should really be about whether Steam will be available for non-x86 Linux environments (particularly ARM). Raspberry Pi doesn't have the processing power, but low cost ARM devices like Ouya with impressive performance are emerging. We all want a low cost open platform games console with Steam on it.

Imagine the amount of work and persuasion this'd take, getting every game dev to cut down their games to run on low-power ARM chips, to recompile all their code for those ARM chips, then distributing it through Steam to the like <1% of the market using ARM as their gaming platform.